It's such a weak argument when defenders of the FBI and democrat corruption cite the failure of its victims to prove that corruption in court (usually in front of a DC jury that voted 92% democrat). Like, that's the point. One side of the political apparatus weaponized the justice system against the other, then covered it up, and obscured any investigation into it through equally corrupt lawfare and political deflection.
I see the same argument attacking the credibility of the whistleblower who was a business partner of Hunter Biden when they received money from the Chinese energy company CEFC - "oh your whistleblower was indicted by the DOJ so he has no credibility" - well, the accusation begs the question that the Republicans are complaining about in the first place, namely why wasn't Hunter Biden similarly indicted for the same FARA violations as his business partner who's blowing the whistle on his lack of indictment? It's flawed logic. You can't cover up your crimes by arresting the criminal you did the crimes with and then saying he's got no credibility because he's a criminal.